Simplify the expression. $(-a-3)(2a+4)$
Explanation: First distribute the ${-a-3}$ onto the ${2a}$ and ${4}$ $ = {2a}({-a-3}) + {4}({-a-3})$ Then distribute the ${2a}.$ $ = ({2a} \times {-a}) + ({2a} \times {-3}) + {4}({-a-3})$ $ = -2a^{2} - 6a + {4}({-a-3})$ Then distribute the ${4}$ $ = -2a^{2} - 6a + ({4} \times {-a}) + ({4} \times {-3})$ $ = -2a^{2} - 6a - 4a - 12$ Finally, combine the $x$ terms. $ = -2a^{2} - 10a - 12$